Gaseous electric discharge lamp device



Dec- 21,' i937. M. J. DRUYvEsTEYN ET AL 2,103,226

GASEOUS ELECTRIC DIS-CHARGE LAMP DEVICE Filed March CL4, 1934 y INVENTORS Marv: Johan Druyveseyn,

Carpe/As Bo/, Mar-mus van Dam,

BYH

@wlw ATT RNEY Patented ec. 21, 1937 UNITED STATES PATENT CFI-ICE 2,103,226 y cAsEoUs ELECTRIC DISCHARGE LAMP DEVICE Application March 14,1934, serial No. 715,462

In Germany March 31, 1933 s Claims. (Cl. 24h-11.4)

The present invention relates to gaseous electric discharge lamp devices generally and more particularly the invention relates to such lamp devices having a gaseous atmosphere Consisting of, or comprising a vaporizab'le material.

When the vaporizable material is of a kind that is at an eiective pressureonly at an elevated temperature, such as an alkali metal, it is advantageous to provide a heat conservator for the gaseous electric discharge lamp device to decrease the radiation of heat from the container of the lamp`device to maintain said container at an elevated temperature during the operation of the device. A double walled jacket is a suitable heat conservator and the space between the device and the jacket and/or the space between the walls of the jacket is either evacuated or lled with a gas having poor heat conductivity characteristics and at a pressure less than atmospheric pressure.

'I'he object of the present invention is to increase the luminous emciency of ai lamp unit of the above type. Another object of the invention is to provide a lamp unit of the above type wherein a greater quantity of light is sent out in one\direction than in other directions. A further object of the invention is to provide such a lamp -unit particularly suitable for illuminating roads or the like. Still further objects and im advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular descrip' tion. A We have discovered that the above objects are attained by mounting two similar dischargelamp devices in the heat conserving jacket in such manner that the longitudinal axis of the tubular container of each of said lamp devices is not coincident with the longitudinal axis of the heat a0 conserving jacket. The tubular containers of the lamp devices are closely adjacent and the adjacent sides thereof radiate heat to each other.

We prefer a separation of the containers less I than twice the diameter of one of said containers and in general the effectiveness of the lamp unit increases as the distance between the Containers decreases. A separation of less than the diameter of one of saidv containers is particularly effective for the contemplated results.

50. The temperature distribution over the Walls of the containers of the discharge lamp devices in a lamp unit having the above structure is such that any light absorbing deposits of condensed material collect on the. walls of the containers adjacent the wall of the heat conserving jacket as these walls are cooler duri g the operation of the device than the adjacent walls of said containers. The adjacent walls on the containers are therefore more transpar nt than the other walls thereof and the light emitted by the 5 lamp unit is more intense in the direction-at right angles to a plane passing through the longitudinal axis of both said containers than in a.

direction in such plane.

gle lamp device having a U-shaped container. In this case the parallel legs of the U-shaped containers are equivalent to individual containers of the two discharge'lamp devices in the embodiment discussed above and the same phenom- 15 ena takes .place therein.

In the drawing accompanying and forming part of this specication two embodiments of the invention are shown but as such illustration is primarily for purposes of disclosure it lwill be o understood of course that numerous changes in thel form and details of the devices and in their use and operation may be made by those skilled in the art without departure from the broad spirit and scope of the invention. 25

Referring to 'the drawing,

Fig. 1 is a side elevational, partly sectional view of one embodiment of the invention,

Fig. 2 is a similar view of another embodiment, of .the invention, 30

Fig. 3 is a sectional view along the lines 3 3 .of Fig. 1, and

Fig. 4 is a light distribution curve of both embodiments of the invention.

The new and novel lamp unitillustrated in 35 Fig. 1 comprises two gaseous electric discharge lamp devices having straight tubular containers l and 2. Each of said containers I and 2 has a pair of electrodes -3 and 4 sealed therein at each end thereof. Said electrodes 3 are thermionicgo cathodes and consist of a lament, such as a tungsten or nickel filament, coated or impregnated with an`electron emitting material, such as barium oxide. Said electrode 4 is a cylindrically shaped sheet metal electrode, .such as a 45Av lium, or zinc.y Mixtures, alloys, or amalgame of these metals are used when desired. The devices illustrated contain a gaseous mixture comprising neon and sodium. We prefer 4to connect the de- For example, when the containers I and 2 have a diameter of 24 mm. the distance between said containers I and 2 is approximately 2 mm The containers I and 2 are mounted on either side of the longitudinal axis of said jacket 5, as shown in Fig. 3 and those parts of said containers I and 2 adjacent the inner wall of said jacket 5 are at a lower temperature during the operation of the device than those parts of said containers I and 2 adjacent each other. Any condensation of the metal vapor which takes place in said containers I and 2 during the operation of the lamp unit occurs on those parts of the walls of said containers adjacent the inner wall of said jacket 5 since these parts are the coolest container parts during the operation of theedevices. The light distribution curve of the lamp unit in the plane 3-3 (Fig. 1) is illustrated in Fig. 4 of the drawing wherein it is shown that a greater quantity of light is sent out in the direction Y-Y than in the direction X-X.

In order that the light emitted by the lamp unit be distributed in accordance with the curves illustrated in Fig. 4 of the drawing it is'desirable that no heat absorbing elements, such as glass supporting elements, be mounted between the ,containers I and 2. The distance between the containers I and 2 should not be too great for otherwise the benecial mutual healing effect between the containers I and 2 will be reduced below that required for the results desired. In

practice we have found that suiiicient heating isI obtained in general when the space between said containers I and 2 is less than twice the diameter of one of said containers I and 2. heating will be greater, of course, the smaller the distance between the containers I and 2. A distance considerably less than the diameter of one of said containers I and 2 is preferred.

The adjacent sides of side containers I and 2 should be highly transmitting to the light rays emitted by the lamp devices and for this reason it is not advisable to apply conducting coatings to the adjacent walls of saidcontainers I and 2 as such coatings are in general highly absorbent of the rays emitted by the lamp devices.

The lamp devices shown in Fig. l of the drawing operate with a'positive column discharge. The lamp unit is useful in connection with highway illumination. When making use of the lamp unit for this purpose the lamp unit is mounted, when desired, over the center of the road and the lamp devices are perpendicular to the plane of the road surface. When desired the lamp devices are mounted horizontal to the plane of the road. Part of the light emitted by the lamp in the Y-Y direction strikes the road directly and the other part thereof is directed to the road surface by means of a reilector mounted above the lamp unit.

' While we have described the @W9 diSChalge The mutuall lamp devices as having the same gaseous atmosphere it will be understood, of course, that we contemplate that each of said devices can have a different gaseous filling in which case the light emitted by the lamp unit is a mixture of the light The embodiment of the invention illustrated in Fig. 2 of the drawing is similar in all respects to that illustrated in Fig. 1 with the exception that in this embodiment a single lamp device having a U-shaped container 6 is used in place of the two lamp devices having straight containers I and 2 illustrated in Fig. 1 of the drawing. The operating characteristics of the lamp unit illustrated in Fig. 2 are the same as that discussed in connection with Fig. 1 and the rules regulating the spacing between the parallel legs of said container 6 are the same as those governing the spacing of said containers I and 2 in the embodiment illustrated in Fig. 1. An auxiliary electrode is mounted in the curved portion of said container 6 to facilitate starting of the lamp device, when desired. The lamp unit is mounted in the same manner as the lamp unit illustrated in Fig. 1, when desired.

While we have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details ofv the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:-

1. A lamp unit comprising in combination, two gaseous electric discharge lamp devices each comprising a straight container, electrodes sealed therein, a gaseous atmosphere therein and a vaporizable metal therein, and an hermetically sealed heat conservator for said lamp devices, said devices being mounted in parallel positions in said conservator, the walls of each of said devices beingseparated from the Walls of said conservator and from the walls of the other of said devices, the distance between said containers being less than twice the diameter of one of said containers to localize the light obstructing deposits of the condensed metal in each of said lamp containers at parts thereof other than those parts adajacent the other of said lamp containers during the operation of said lamps.

2. A lamp unit comprising in combination, a gaseous electric discharge lamp device comprising a U-shaped container, electrodes sealed therein, a gaseous atmosphere therein and a vaporizable metal therein, and an hermetically sealed heat conservator for said lamp device, the walls of said lamp being separated from the walls of said conservator, the distance between the parallel legs of said U-shaped container being less than twice the diameter of one of the legs of said container to localize the light obstructing deposits of the condensed metal in each leg of said lamp container at parts of said legs other than those parts adjacent the other of said legs during the operation of said lamp.

3. A lamp unit comprising in combination. a luminous, tubular element having a vaporizable material therein and having parallel parts, an

hermetically sealed heat conservator for said moana@ jacent the other of said pms duimg ation of said MAR'I'INUS VAN DAM.

luminous element.

MARI JOHAN DRUYVESTEYN. WILLEM UYTERHOEVEN. CORNELIS BOL.

the oper- 

